The present invention relates to a quick coupler for coupling an implement to a tractor, and more particularly relates to an improved latching mechanism therefor.
Commercially available quick couplers, such as described in U.S. Pat. No. 3,544,133, have a pair of laterally spaced-apart hooks, each with a latching mechanism for releasably holding an implement hitch pin in the hook. The latching mechanism typically includes a latch coupled to an operating bar by one or more pivotal links.
If the operator moves such a quick coupler backwards against an implement while inadvertently leaving the latch in the locked position, then a large force may be applied laterally in the forward direction to the latch due to engagement of the hitch pin with the exposed and locked latch. In some known quick coupler latch mechanisms, this loading force could cause a bending deformation of the control bar or of the links and pivot pins which connect the latch to the control bar.
Such bending failures are undesirable because they may not be noticeable upon an inspection of the exterior of the device. Then, if such a damaged device is put in service, it may fail to latch properly at one side of the quick coupler. If this happens, then the hitch pin can be forced out of the damaged side and the resulting twisting load on the other (undamaged) coupler side can create costly damage to the structural parts on the undamaged side of the coupler frame. One response to this problem has been the introduction of self-opening latch mechanisms, such as described in U.S. Pat. No. 3,807,769 and in U.S. Pat. No. 3,531,140. However, such self-opening latch mechanisms are more complicated and costly than the simpler, non-self-opening types. Accordingly, it would be desirable to provide a simple, quick coupler latch mechanism which is resistant to bending failures.